DSD Conversion Occurring?

Dear Tech Gurus: I have a Perfect Wave SACD Transport connected to a DirectStream Mk 2 DAC and an Airlens. When I am playing a CD or SACD on the Perfect Wave,the information screen always indicates PCM. Does that mean that the disc is being played in PCM without DSD conversion,or does it just tell me that the original source material was PCM,but still being converted to DSD? Thanks for all assistance. Matt

It could be that the SACD layer is set to CD rather than DSD.

From page 16 of the owners manual:
“Layer: Toggles between DSD and CD layer on SACDs.”

What @st50maint mentioned above is certainly the first thing to check. But could you say more about your set up? You mentioned a connection to the AirLens, which I do not understand in reference to the SACD transport. The transport should be connected directly to the DAC, preferably utilizing one of the I2 S connections. PSA worked out an arrangement with Sony that allows the digital SACD data to be passed to the DAC, but only if the transport is connected to a PSA DAC. If the “handshake“ between the two pieces is not recognized, only the CD data will be read off the disk. As I recall, the handshake requires the use of an I2S connection; so if you’re using, for instance, coax you’re only getting CD quality.

Trust the screen. If it says PCM that’s what’s being sent to the DAC.

Thanks for your thoughts. The SACD transport is set to DSD. The Direct Stream DAC is connected to the Airlens via the I2s connections. Paul says “Trust the Screen”. So,how do I get the DSD conversion,rather than passing on the PCM,only? Matt

What is the screen on the SACD transport reporting that it is sending?

The PST does not do any conversion; it only passes what it reads on to the DAC. If PCM data arrives at the DS DAC, it is converted to DSD by the DAC and upsampled to a very high rate. If SACD data arrives, it is also upsampled but does not need to be converted since it is already DSD (single-rate, aka DSD 64). The screen on the DAC will indeed show you what is coming in.

The AirLens has nothing to do with any of this.

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Generally,the screen states PCM 24.88. Thanks, Matt

It looks like there are two relevant menu items.
Layer and Layer Default.
Are they both set to DSD?

Thanks for posing a good question. Where are the Layer and Layer default menu items- on the Airlens,on the DAC or on the Perfectwave transport? I have gone through the menu settings for each and can’t locate a Layer or Layer Default option. Appreciate the assistance

On the transport, press and hold the button to the left of the display until the gear icon appears on screen (this is the same button you use to open and close the disk drawer). Then use the right arrow key to scroll through the menu options until you come to the layer setting. These options are illustrated on page 16 of the manual; if you don’t have a copy, you can download one from the Support tab on the PSA website.

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You da man,David. Thanks for the info. Matt

It’s working now?

The #1 mind-blowing trick that Ted delivered in the DS family is that incoming PCM and DSD are treated exactly the same. They are both directly upsampled using the exact same low-pass filters (lower rate PCM goes through one or two initial passes that DSD and high rate PCM don’t need) to an extremely high sampling rate at more than 50 bits of resolution, including optional scaling for volume. Then that data is processed using an SDM to produce new DSD output bits for direct conversion to analog.

There are no options in that process: it has only one way of operating.

So the display on the DAC is only telling you what kind of data it’s receiving on its inputs. If you think the DAC should be receiving DSD but it says PCM, then something prior to the DAC is where you need to investigate.


Thanks for expressing more precisely what I wanted to convey. Hopefully the OP has got this all sorted out now.

Affirmative. Thanks,all.

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